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United States Patent |
5,733,503
|
Kowatsch
,   et al.
|
March 31, 1998
|
Method for vapor sterilization of articles having lumens
Abstract
A method and device for enhancing the vapor sterilization of the lumen of
medical instruments and like articles under reduced pressure. A vessel
containing a small amount of a vaporizable liquid antimicrobial solution
is attached to the lumen. The antimicrobial vaporizes and flows directly
into the lumen of the article as the pressure is reduced for the
sterilization cycle. Preferred embodiments illustrate a sealed chamber
containing the antimicrobial and an opener for opening the chamber with
the device already attached to the article. Preferably, the opener
comprises a hollow spike. A ring between the opener and chamber must be
removed prior to opening the chamber and removal of the ring destroys the
ring so that it can not be replaced.
Inventors:
|
Kowatsch; Reinhard (Hamburg, DE);
Soto; Toby (Fort Worth, TX);
Howlett; Charles (Laguna Beach, CA)
|
Assignee:
|
Johnson & Johnson Medical, Inc. (Arlington, TX)
|
Appl. No.:
|
758515 |
Filed:
|
December 2, 1996 |
Current U.S. Class: |
422/28; 422/292; 422/294; 422/305 |
Intern'l Class: |
A61L 002/20 |
Field of Search: |
422/28,33-37,25,292,294,301,305
220/278
604/411,415
|
References Cited
U.S. Patent Documents
1817530 | Aug., 1931 | Spanel.
| |
2688428 | Sep., 1954 | Manhartsberger.
| |
3371985 | Mar., 1968 | Wyka.
| |
3688985 | Sep., 1972 | Engel.
| |
3730434 | May., 1973 | Engel.
| |
4152378 | May., 1979 | Wcelka et al.
| |
4169123 | Sep., 1979 | Moore et al.
| |
4380530 | Apr., 1983 | Kaye.
| |
4410492 | Oct., 1983 | Kaye.
| |
4525220 | Jun., 1985 | Sasa et al.
| |
4526622 | Jul., 1985 | Takamura et al.
| |
4526623 | Jul., 1985 | Ishii et al.
| |
4576650 | Mar., 1986 | Yabe et al.
| |
4579597 | Apr., 1986 | Sasa et al.
| |
4579598 | Apr., 1986 | Sasa et al.
| |
4643876 | Feb., 1987 | Jacobs et al.
| |
4675159 | Jun., 1987 | Al-Sioufi.
| |
4756882 | Jul., 1988 | Jacobs et al.
| |
4808381 | Feb., 1989 | McGregor et al.
| |
4867326 | Sep., 1989 | O'Meara.
| |
4943414 | Jul., 1990 | Jacobs et al.
| |
4956145 | Sep., 1990 | Cummings et al.
| |
5084239 | Jan., 1992 | Moulton et al.
| |
5171214 | Dec., 1992 | Kolber et al.
| |
5186893 | Feb., 1993 | Moulton et al.
| |
5244629 | Sep., 1993 | Caputo et al.
| |
5260021 | Nov., 1993 | Zeleznick.
| |
5288460 | Feb., 1994 | Caputo et al.
| |
5310524 | May., 1994 | Campbell et al.
| |
5362444 | Nov., 1994 | Amtower.
| |
5364386 | Nov., 1994 | Fukuoka et al.
| |
Other References
Fisher Scientific Catalogue, pp. 46c-47c (1983).
Product Label for Sterrad* Adapter (1993).
Directions for Use Sterrad* Adapter (1994).
|
Primary Examiner: Snay; Jeffrey
Parent Case Text
This is a division of application Ser. No. 08/436,999, filed May 8, 1995,
now U.S. Pat. No. 5,580,530, which is a continuation-in-part of Ser. No.
08/120,303, filed Sep. 13, 1993, which is a continuation of Ser. No.
07/864,151, filed Apr. 2, 1992, now abandoned, which is a continuation of
Ser. No. 07/464,843, filed Jan. 16, 1990, now abandoned, which is a
division of Ser. No. 07/079,550, filed Jul. 30, 1987, now U.S. Pat. No.
4,943,414.
Claims
What is claimed is:
1. A method for sterilizing an article lumen comprising the steps of:
enclosing an antimicrobial solution in a sealed chamber of a first member,
the sealed chamber having a thin wall;
connecting a second member in moveable relation to the first member, said
second member comprising an opening member;
connecting the wall to the article lumen so that the wall is in fluid
communication with the article lumen; and then
moving the second member in a predetermined direction relative to the first
member and thereby moving the opening member toward the wall so as to open
the wall and place the chamber into fluid communication with the article
lumen; and
isolating a user from the antimicrobial solution during the process of
opening the chamber.
2. A method according to claim 1 and further comprising the step of
inserting a safety guard between portions of the first and second members
to limit motion of the second member in the predetermined direction and
further comprising the step of removing the safety guard prior to the step
of moving the second member in the predetermined direction.
3. A method according to claim 1 and further comprising the step of
reducing the pressure within the article lumen thereby drawing the
antimicrobial solution into the article lumen.
4. A method according to claim 1 and further comprising the step of drawing
the antimicrobial mixture from the sealed chamber into the article lumen
through a mist filter to limit the passage of liquid antimicrobial mixture
into the article lumen in preference to vapor phase antimicrobial mixture.
5. A method according to claim 1 wherein the antimicrobial mixture is
hydrogen peroxide.
6. A method according to claim 1 wherein the step of opening the wall
comprises penetrating the wall with at least a portion of the second
member.
7. A method according to claim 6 wherein the portion of the second member
that penetrates the wall comprises a spike with a hollow bore therethrough
and further comprising the step of placing the chamber into fluid
communication with the article lumen through the bore of the spike.
8. A method according to claim 1 and further comprising the step of
interconnecting the first and second members in telescoping relationship
with each other.
9. A method according to claim 8 and further comprising the steps of
providing a threaded connection between the first and second members and
wherein the step of moving the second member in a predetermined direction
relative to the first member comprises rotating the first and second
members relative to each other about the threaded connection thereby
telescoping the first and second member relative to each other.
10. A method according to claim 1 and further comprising the step of
permanently sealing the antimicrobial mixture in the sealed chamber in
such a fashion that the sealed chamber can only be opened by deforming a
portion thereof, and wherein the step of opening the sealed chamber
comprises the step of breaching the thin wall with the opening member,
whereby accidental release of the antimicrobial mixture from the sealed
chamber is lessened, yet the mixture is easily released by operation of
the opening member.
11. A method according to claim 10 wherein the sealed chamber is sealed by
welding a cover thereto.
12. A method according to claim 10 wherein the sealed chamber is sealed by
gluing a cover thereto.
13. A method according to claim 12 wherein the cover and chamber are formed
of plastic and the cover is sonically welded to the chamber.
Description
BACKGROUND OF INVENTION
1. Field of Invention
The invention relates to the vapor sterilization of articles such as
medical instruments having long narrow lumens therein, and more
particularly, to a device for delivering a gaseous antimicrobial directly
into the lumen of an article during the sterilization process.
2. Background Information
The need to sterilize articles such as medical instruments and others for
use in the agriculture and fermentation industries is well known. In
recent years, many methods of vapor sterilization have been developed.
While these methods offer the advantage of being generally faster than
sterilization by immersion in an antimicrobial solution, they suffer from
one major disadvantage, namely the inability to sterilize the interior of
a long narrow tube in a short period of time. Thus, with regard to medical
instruments such as endoscopes, the difficulty in sterilizing the lumen
can often negate the general advantage of using vapor sterilization.
One way of overcoming the above disadvantage is set forth in U.S. Pat. Nos.
4,410,492 and 4,337,223. The apparatus described therein comprises a
sterilizing chamber with means for introducing an antimicrobial gas into
the chamber and circulating the gas within the chamber. Disposed within
the chamber is a socket for receiving the tubular end of a medical
instrument. The socket is connected to a valve and a recirculating pump
and the antimicrobial gas is recirculated from the chamber through the
lumen of the instrument. The commercial apparatus employs ethylene oxide
as the antimicrobial and requires a sterilization times of about 3 hours
for flexible endoscopes and about 2 hours for the shorter, rigid
endoscopes. Ethylene oxide is a known toxic substance and the process
thereby experiences concomitant toxicity problems. In addition, the method
and apparatus described in these references cannot be used to sterilize an
instrument within a sterile pack since one end of the instrument must be
attached to the socket.
Thus there is a current need for an effective method to sterilize medical
instruments such as endoscopes in a reasonably short period of time,
preferably in one hour or less. The method and device of the present
invention makes vapor sterilization of such instruments practical by
delivering vapor directly to the interior of the lumen in the endoscope,
whether or not it is in a sterile pack.
SUMMARY OF THE INVENTION
The present invention comprises a method for providing antimicrobial vapor
directly into the long narrow lumen of medical instruments and similar
articles. The method for sterilizing an article lumen according to the
present invention comprises the steps of enclosing an antimicrobial
solution in a sealed chamber of a first member, the sealed chamber having
a thin wall; connecting a second member in moveable relation to the first
member; connecting the wall to the article lumen so that the wall is in
fluid communication with the article lumen; and then moving the second
member in a predetermined direction relative to the first member and
thereby moving the opening member toward the wall, opening the wall and
placing the chamber into fluid communication with the article lumen. A
user is isolated from the antimicrobial solution during the process of
opening the chamber.
Preferably, a safety guard is placed between portions of the first and
second members to limit motion of the second member in the predetermined
direction. The safety guard is removed prior to the step of moving the
second member in the predetermined direction. By reducing the pressure
within the article lumen, the antimicrobial solution is drawn into the
article lumen. Preferably, the step of opening the wall comprises
penetrating the wall with at least a portion of the second member, which
can comprise a spike with a hollow bore therethrough thereby placing the
chamber into fluid communication with the article lumen through the bore
of the spike. Preferably, the first and second members are interconnected
in telescoping relationship with each other, and may be threaded together
as well.
Preferably, the antimicrobial mixture is permanently sealed within the
sealed chamber in such a fashion that the sealed chamber may only be
opened by deforming a portion thereof. The sealed chamber would then be
opened by breaching the thin wall with the opening member. Thus,
accidental release of the antimicrobial mixture from the sealed chamber is
lessened, yet the mixture is easily released by operation of the opening
member. The chamber can be sealed by gluing or welding a cover thereto.
The cover may also be sonically welded to the chamber.
Preferably, the antimicrobial mixture is drawn from the sealed chamber into
the article lumen through a mist filter to limit the passage of liquid
antimicrobial mixture into the article lumen in preference to vapor phase
antimicrobial mixture. The antimicrobial mixture preferably comprises
hydrogen peroxide.
With the use of the method of the present invention, vapor sterilization
times for endoscopes can be reduced to one hour or less. In addition, the
method may be used to sterilize endoscopes in a sterile pack since the
device of the present invention may be attached to and packaged with the
endoscope before the endoscope is placed within the sterilization chamber.
Upon opening of the pack, the device may be retrieved for re-use or
preferably discarded with the pack.
The method of the present invention reduces sterilization time required for
instruments having long narrow lumens therein. Reduced sterilization times
are also achieved with the instruments encased in a package designed to
maintain sterility after the removal from the sterilized chamber. In
addition, as antimicrobial vapor is provided directly into the lumen of
the instrument, lower concentrations of antimicrobial solutions may be
used in the sterilizer, and this together with the reduced sterilization
times provides improved materials compatibility with respect to both the
instrument components and the packaging or wrapping materials.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of one embodiment of the device, according to
the present invention, attached to the end of a tube;
FIG. 2 is a perspective view of another embodiment of the device of the
present invention, showing the end of the device for making a connection
to a tubular member;
FIG. 2A is a perspective view of a variation of the device of FIG. 2;
FIG. 3 is a plan view of another embodiment of a device of the present
invention;
FIG. 3A is a variation of the device of FIG. 3;
FIG. 4 is a plot of sterilization time verses efficacy and showing enhanced
efficacy of attaching an H.sub.2 O.sub.2 device to a lumen prior to
sterilization;
FIG. 5 is an exploded view of a further embodiment of a device of the
present invention;
FIG. 6 is an exploded view in section of the device of FIG. 5;
FIG. 7 is an end view of the opener of the device of FIG. 5;
FIG. 8 is a plan view in section of the assembled device of FIG. 5, prior
to use;
FIG. 9 is a plan view in section of the assembled device of FIG. 5, during
use;
FIG. 10 is a perspective disassembly view of a further embodiment of a
device of the present invention;
FIG. 11 is a plan view in section of the assembled device of FIG. 10,
during use;
FIG. 12 is a close-up plan view of a distal portion of a capsule portion of
the device of FIG. 10; and
FIG. 13 is a sectional view taken along lines 13--13 of FIG. 12.
DETAILED DESCRIPTION OF THE INVENTION
The method and device of the present invention relates to the sterilization
of articles such as medical instruments having a long narrow tube therein.
The term instruments as used herein applies to medical or surgical devices
such as endoscopes, catheters, tubing, or similar instruments or articles
having an internal lumen which is preferably used in a sterile condition
as in, for example, the agricultural or fermentation industries. The
method and device of the present application show particular advantages in
the solution vapor sterilization of lumens exceeding ten centimeters in
length and having an internal diameter of about 7 millimeters or less. As
endoscopes typically have lumens with internal diameters of 1 to 4
millimeters and lengths of up to 1.5 meters or more for flexible
endoscopes and at least 45 centimeters for rigid endoscopes, the method
and device of the present application have particular applicability to the
sterilization of these instruments. With the use of the device of the
present invention, antimicrobial vapor is supplied directly to the lumen
or interior of the tube of the instrument during the vapor sterilization
process.
The antimicrobials used with the method and device of the present invention
include solutions of glutaraldehyde, hydrogen peroxide, chlorine dioxide
or other antimicrobials in an inert solvent, the only requirement being
that the solution be liquid at atmospheric pressure and a vapor at the
temperature and pressure of the sterilization process. Though the higher
concentration solutions of antimicrobials are more effective, problems
with materials compatibility and shipping and handling may arise at very
high concentrations. For example, a 30% to 50% solution of hydrogen
peroxide in water is both very effective and presents few shipping and
handling problems, while higher concentrations of up to 70% become
increasingly more difficult and dangerous to handle.
In solution vapor sterilization, the procedure generally used is as
follows: The article to be sterilized is placed within the sterilization
chamber, the chamber is sealed, and a vacuum is drawn on the chamber to
reduce the pressure to less than about 50 torr, and preferably to 20 torr
or less. An antimicrobial solution is then injected into the chamber where
it vaporizes and contacts the exposed surfaces of article. The time
necessary for total kill of specific microbial agents varies with the type
and concentration of antimicrobials present, and with the degree of
exposure to the microbial agent. Microbials disposed in cracks, crevices
or internal tubular structures are somewhat protected from the
antimicrobial agent and require more time for total kill than microbials
on the external surface of the article. Heat or high frequency radiation
may be used to increase the effectiveness of the antimicrobial and its
penetration into remote areas of the instrument.
The device of the present invention comprises a vessel for containing a
small amount of antimicrobial solution, and a means for connecting the
vessel directly to the lumen or the end of the tube of the article to be
sterilized. When the article with device containing antimicrobial solution
is disposed in the sterilization chamber and a vacuum drawn on the
chamber, antimicrobial vapor generated from the solution within the vessel
flows directly into the lumen.
The effectiveness of the method and device of the present invention was
demonstrated by the following experiments:
50 inch (127 centimeters) lengths of Tygon tubing having a 2 millimeter
inside diameter were used to simulate an endoscope in the sterilization
test. A paper strip (2 mm.times.13 mm) containing approximately
2.0.times.10.sup.6 Bacillus subtilis (var. globigii) spores was placed in
each tube equidistant from each end. A syringe containing 0.05 milliliters
of 10% by weight hydrogen peroxide solution in water was provided for each
tube. Each of the samples was individually packaged in a
TYVEK.TM./MYLAR.TM. envelope prior to sterilization.
One third of the samples (three units) were placed in the package with the
syringe unattached to the end of the tube. Another one-third of the
samples were packaged with the syringe attached. Individual samples were
placed within a 65 liter sterilization chamber and sent through a hydrogen
peroxide vapor sterilization cycle wherein the pressure within the chamber
was reduced to 3 torr for the total exposure time minus 15 minutes, and
0.5 torr for the final 15 minutes of exposure. No additional hydrogen
peroxide was injected into the chamber.
The remaining one-third of the samples, packaged with the syringe attached
to the end of the tube as described above, were sent through a hydrogen
peroxide vapor sterilization cycle supplemented with high frequency
radiation plasma which is known to generate an active species from the
hydrogen peroxide. Again a 65 liter chamber was used, and the pressure
within the chamber was reduced to 3.0 torr for the total exposure time
minus 15 minutes and 0.5 torr for the final 15 minutes of exposure. Again,
no additional hydrogen peroxide was injected into the chamber. Plasma was
generated only during the final 15 minutes of exposure at 2.05 MHz with
320 watts of power, pulsed 0.3 milliseconds on to 1.0 milliseconds off.
At the conclusion of the sterilization cycle, the paper strip was removed
from each tube and placed in a glass vial containing 10 ml of a sterile pH
7.0 phosphate buffer solution. This solution contained 10 milligrams of
TWEEN 80 to aid in removal of any spores from the paper strip and 0.0066
milligram of catalase to neutralize any remaining hydrogen peroxide. Five
glass beads were placed in the solution, and the solution was vortexed for
two minutes to completely macerate the paper strip. Three decimal
dilutions of the solution were made with sterile pH 7.0 phosphate buffer,
and the original solution and the decimal dilutions were poured into
sterile glass Petri plates. A culture medium was added and the plates were
incubated for four days at 30.degree. C. After incubation the number of
viable organisms in each plate was counted, and the number of spores on
the paper strip calculated by multiplying the spore count by the
appropriate dilution factor.
The results of the experiments are presented in Table I below, and plotted
in FIG. 4, where S/S.sub.0 represents the ratio of the number of organisms
surviving the test to the initial number of organisms which were placed on
the paper strip prior to the test. As shown by these data, no reduction in
microbial population was achieved in samples where the syringe was not
attached to the tubing, even after an exposure time of 75 minutes.
Attaching the syringe to the end of the tube according to the method of
the present invention produced total kill in 35 minutes without low
temperature gas plasma, and in 25 minutes when the antimicrobial activity
was enhanced by the use of low temperature gas plasma.
TABLE I
______________________________________
Sterilization
Sample Time - Min.
Efficacy (S/S.sub.0)
______________________________________
A 35 8.6 .times. 10.sup.-1
45 8.9 .times. 10.sup.-1
75 1.1 .times. 10.sup.0
B 20 7.0 .times. 10.sup.-1
25 5.8 .times. 10.sup.-1
35 0
C 20 8.5 .times. 10.sup.-3
25 0
35 0
______________________________________
Sample A -- Syringe unattached
Sample B -- Syringe attached
Sample C -- Syringe attached plus plasma
A preferred embodiment of the device to be used in accordance with the
teaching of the present invention is shown in FIG. 1. The device indicated
generally at 10 is shown attached to a tube 12. In the device depicted in
FIG. 1. The means for connecting the vessel 14 to the end of the tube
comprises an expandable sheath 16, one end of which is securely attached
to the vessel, and the other end of which comprises an elastic ring 18
making a releasable attachment about the end of the tube. The sheath 16
may be attached to the vessel in any known manner and, as shown in FIG. 1,
the sheath 16 is attached to the vessel by a second elastic ring 20
disposed over the lip 22 about opening 24 of vessel 14. Though the vessel
shown is cylindrical, the vessel may comprise any three dimensional
container preferably of semi-rigid material, having an opening therein.
The vessel may be made of, e.g., polyethylene, polypropylene, glass or any
other material which is nonreactive to the antimicrobial solution of
vapor. The sheath may also be formed of polyethylene, polypropylene or
other material which is relatively nonreactive to the antimicrobial vapor.
The elastic rings may be formed of natural latex or butyl rubber which are
relatively resistant to the antimicrobial vapors; however, resistivity is
less critical when the device is constructed for one time use. Disposed
within the vessel may be a substrate 26 comprising a woven or nonwoven
fabric or sponge for containing the liquid antimicrobial solution. The
vessel preferably has a means 28 associated with the opening for attaching
a closure cap over the opening prior to use in order to maintain the
antimicrobial solution therein. As shown in FIG. 1, means 28 comprises
threads for a screw cap fitting about the lip of the vessel.
Another embodiment of the device of the present invention is depicted in
FIG. 2 where the device is indicated generally at 30. The means for
connecting the vessel 34 to the end of a tubular instrument comprises a
bushing 36 disposed within the open end of the vessel. In the particular
embodiment shown in FIG. 2, the bushing comprises a series of rings 38 and
40 of inwardly extending plastic flaps defining a flexible aperture 32 to
receive the tubular instrument. The flaps can be made of any flexible
material which is nonreactive to the antimicrobial solution or vapor, such
as polyethylene, and of sufficient thickness that the flaps provide
resistance to withdrawal of a tube inserted through the aperture. Disposed
within the vessel is a substrate 42 containing the antimicrobial solution.
Preferably, the vessel 34 is provided with means 44 for attaching a
closure cap thereto prior to use. As shown in FIG. 2, means 44 comprise
threads for attaching a screw cap (not shown) within the opening of the
vessel.
FIG. 2A illustrates a variation in the design of the device of FIG. 2 which
utilizes the same basic vessel and means for attachment to a tubular
device. In the device shown in FIG. 2A, end 45 of the vessel opposite the
open end is provided with aperture 46 for attaching a disposable cartridge
47 containing a supply of antimicrobial on a substrate such as a woven or
nonwoven fabric or sponge 48 as illustrated. The aperture 46 of the vessel
is designed in conjunction with neck 49 of the cartridge to provide quick
and easy attachment and release of the cartridge and the vessel. In the
embodiment shown in FIG. 2A, aperture 46 is provided with reverse threads
for engaging the threads of the neck 49 of the cartridge. In this
variation of the device it is not necessary for a substrate containing the
antimicrobial solution to be disposed within the vessel since the
antimicrobial solution is provided in pre-measured aliquots in the
cartridges. With the device of FIG. 2A one achieves the convenience and
accuracy of disposable, pre-measured aliquots of antimicrobial solution
without the expense associated with the device of FIG. 2.
The following table sets forth the effectiveness of the devices depicted in
FIGS. 1 and 2 in a sterilization procedure described below.
TABLE II
______________________________________
Effect of Devices on Efficacy of Sterilization Inside Tubes
Efficacy (S/S.sub.0)
I.D. Length No Device Device
Material (cm) (cm) FIG. 1 FIG. 2A
______________________________________
Surgical Tygon
0.64 10 0 -- --
0.64 20 4.4 .times. 10.sup.-5
-- --
0.64 30 1.1 .times. 10.sup.-2
-- --
0.64 45 8.8 .times. 10.sup.-1
0 0
Rubber Tubing
0.64 25 1.7 .times. 10.sup.-1
-- --
0.64 45 7.9 .times. 10.sup.-1
0 0
______________________________________
The efficacy is recorded in terms of the ratio of the number of
microorganisms surviving the test, S, to the number of challenge
organisms, S.sub.0 (approx. 1.times.10.sub.6) on a paper strip disposed
within the tube equidistant from the ends. In the sterilization procedure,
100 microliters of 30% aqueous H.sub.2 O.sub.2 solution was supplied in
each of the devices. The devices were attached to the ends of tubes of the
indicated length and 0.64 cm in internal diameter. All of the tube samples
were placed within TYVEK'/MYLAR' packaging prior to sterilization. The
packaged tubes were placed within the sterilizing chamber and the pressure
therein was reduced to about 0.1 torr in about 10 minutes. Additional 30%
H.sub.2 O.sub.2 solution was injected into the chamber to achieve a
concentration of 2.0 milligrams H.sub.2 O.sub.2 per liter of chamber
volume. Following injection of the H.sub.2 O.sub.2, the tubes were
retained in the chamber an additional 50 minutes.
Injection of the H.sub.2 O.sub.2 solution raised the pressure in the
chamber to about 6 torr and the pressure was again reduced to about 0.1
torr. During the last 10 minutes of exposure, low temperature gas plasma
was generated in the chamber at 300 watts. The challenge micro organisms
used in the test were Bacillus subtilis (var. globigii) spores.
As shown in Table II above, when the tube length was only 10 centimeters,
sterilization was achieved without the use of the device according to the
present invention. However, for tubing of 20 and 30 centimeters in length,
a device of the present invention would be needed in order to achieve
sterility within the exposure time of the test. For tubes of 45
centimeters in length, total kill was achieved during the 1 hour exposure
time of the test, using either of the devices depicted in FIG. 1 and FIG.
2.
A further experiment used 7 mm medical grade Teflon tubing 183 cm in
length. The tubing was cut into three pieces to obtain a 5 cm long center
section which was joined in the end sections by external tubing
connectors. In the experiment, approximately 1.0.times.10.sub.4 Bacillus
(var. globigii) spores were deposited in the center section of the Teflon
tubing. The tubing was assembled and subjected to sterilization with
hydrogen peroxide vapor as described above at a concentration of 2.0
mg./liter of chamber volume. The chamber was evacuated to a pressure of
0.1 torr before the peroxide was injected as an aqueous solution and
allowed to vaporize. After 20 minutes, a continuous gas plasma was
generated in the chamber at 300 watts, 13.5 MegaHertz and the
sterilization continued for an additional 5 minutes after which the vacuum
was released with sterile, filtered air, and the number of surviving
spores determined.
The experiment was first conducted without a device of the present
invention attached to the tubing, then repeated with a device of FIG. 3 as
described below containing 100 ml of 30% hydrogen peroxide attached to one
end of the tubing. The experimental results of the tests are presented in
Table III below.
TABLE III
______________________________________
Sterilization of 1 mm Tubing Efficacy (S/S.sub.0)
Material I.D. Length No Device
FIG. 1 Device
______________________________________
Teflon 1 mm 183 cm 1.9 .times. 10.sup.-1
0
______________________________________
The data of Table III demonstrate the efficacy of the method of the present
invention in sterilizing of very long tubes having very small diameters
used in certain endoscopic procedures.
Additional embodiments of the device of the present invention are depicted
in FIGS. 3 and 3A. The device shown in FIG. 3 indicated generally at 50,
comprises a vessel 52 in the form of a pouch constructed of a flexible
material. The means for connecting the vessel or pouch 52 to the end of an
instrument tube comprises a first drawstring 54, and preferably a second
drawstring 62. These drawstrings are preferably arranged in the
configuration as shown in FIG. 2 to be drawn from opposite sides of the
pouch. The pouch is preferably provided with an airtight seal to maintain
the antimicrobial solution therein prior to use, and includes a means for
creating an opening in the sealed pouch so that it may be disposed over
the end of a tube. The seal may be created by sealing the ends 66 of the
pouch, and of the lumen as often the means for opening the sealed pouch
may comprise, for example, a line of weakening at 68, preferably in
combination with a notch also shown generally at 68, to permit the pouch
to be opened by tearing off one end.
FIG. 3A shows a device indicated generally at 50A, similar to device 50,
but wherein the airtight seal and the means for creating and opening the
sealed pouch is a line of fastening 64 similar to a "zip-lock" closure.
Optionally, opening flaps 70 may be provided on either side of the pouch
adjacent closure 64 of FIG. 3A, or the line of weakening 68 of FIG. 3.
These flaps are firmly secured to the pouch. In use, after the sealed end
66 of the pouch of FIG. 3 has been removed along the line of weakening 68,
the flaps when pulled oppositely from each other will distend the opening
of the pouch for disposal around the end of an instrument tube. The flaps
of FIG. 3A, when pulled in opposite directions, can be used to open the
zip-lock fastening, or if the fastening is already opened, to distend the
opening for disposal around the end of an instrument tube. A substrate 72
such as a woven or nonwoven fabric or sponge may be disposed within the
pouch for containing the antimicrobial solution.
In a preferred construction, the drawstrings are provided with a locking
means as illustrated. Though many means for locking or catching a
drawstring are known in the art and may be used in conjunction with the
present invention, the locking means depicted at 56 at FIG. 3 comprise a
catch 60 for a serrated edge 58 provided on the drawstring. As shown in
FIG. 3, the catch, comprising an opening for disposing one end of the
drawstring therethrough, is located at the opposite end of the drawstring.
The catch, however, may be provided by a flap, opening therein, attached
to the edge of the pouch, provided the other end of the drawstring must
also be attached to the pouch. When two drawstrings are used, one or both
drawstrings may be provided with a locking means. By pulling the end 73 of
the drawstring, the flexible pouch is gathered and a firm fastening may be
made to a tube inserted within the pouch.
Preferably, a highly concentrated solution of hydrogen peroxide is used as
the liquid antimicrobial in the device of the present invention. However,
in high concentrations, hydrogen peroxide can quickly cause damage to
living tissue. A system for applying such solution to an instrument lumen
while reducing the chances of accidental exposure of a user to the
antimicrobial solution is highly desirable. The following embodiments
provide such advantage.
FIG. 5 illustrates a further embodiment of a device 100 according to the
invention. The device 100 comprises in gross a capsule 102, an opener 104,
and a safety ring 106 positioned between the capsule of 102 and the opener
104. Turning to FIG. 6, the capsule 102 comprises a cylindrical body 108
having a distal end 110 and a proximal end 112. At the proximal end 112,
the capsule body 108 expands radially to form a cup shaped well 114. A
membrane wall 116 is disposed within the capsule body 108 adjacent to well
114.
A cap 118 of generally discoidal shape has a distally projecting annular
flange 120 which fits within the well 114. The cap 118 is sonically welded
to the capsule 102 at the proximal end 112 to seal a quantity of
antimicrobial solution 122 within a chamber 124 defined between the cap
118, membrane wall 116 and capsule body 108. During storage the
antimicrobial solution 122 may tend to diffuse through the capsule 102 and
out of the chamber 124 thereby decreasing its quantity and potency. The
antimicrobial solution 122 thus preferably comprises 197 mg of 59%
hydrogen peroxide solution upon construction such that after a reasonable
storage period such as ten months, the chamber 124 will retain
approximately 100 mg of a 45% hydrogen peroxide solution.
So that it may be more easily breached, a central portion 126 of the
membrane wall 116 has a slightly thinner thickness than the remainder of
the membrane wall 116. Six radial ribs 128 extend from the capsule body
108 towards, but not into, the membrane wall central portion 126 to
support the membrane wall 116 during the breaching process.
At the capsule body distal end 110, an annular flange 130 slopes outwardly
and proximally, thus providing a barbed appearance in cross-section. The
distal flange 130 preferably slopes in a gentle fashion, such as a
17.degree. slope from an imaginary coaxial centerline 132 of the device
100. A central annular flange 134 slopes outwardly and proximally from the
capsule body 108 at a slightly more aggressive angle than the distal
flange 130. A pair of diametrically opposed slits 136 extend proximally in
the capsule body 108 from its distal end 110 to allow some flexibility in
the capsule body 108 and to thereby ease its entry into the opener 104.
The opener 104 comprises a cylindrical body 140 having a proximal end 142
facing the capsule 102 and a distal end 144. A hollow spike 146, coaxially
disposed within the opener body 146, extends toward the membrane wall 116
and terminates in a beveled and sharpened tip 148. Preferably, the tip 148
is beveled at a 30.degree. angle from the device center line 132. Also, a
central lumen 150 extends coaxially through the spike 146.
Three equilaterally spaced posts 152 extend outwardly radially from a fixed
end of the spike 146 to the opener body 140 and thereby support the spike
146 therein. Preferably, each of the posts 152 has a distally facing
fillet brace 154 for added support. A circumferentially interrupted
annular embossment 156 extends radially inwardly in a very shallow manner
from the opener body 140 (see also FIG. 7). When the capsule 102 is
inserted into the opener 104 with the capsule distal flange 130 beyond the
opener embossment 156, engagement therebetween prevents the capsule 102
from being easily removed from the opener 104 while still allowing a
relative degree of movement between the opener 104 and capsule 102 as will
be more fully described hereinafter.
A retaining ring 158 holds a mist-filter screen 160 within the opener body
distal end 144. The mist-filter screen 160 is round with a diameter
exceeding that of the opener body 140 whereby it is frictionally retained
within the opener body 140 by the retaining ring 158. Preferably, the
mist-filter screen 160 has a mesh opening of 105 microns and is formed of
polypropylene. A plurality of axially aligned embossments 162 on an outer
surface of the retaining ring 158 ease insertion and securely retain the
mist-filter screen 160 and retaining ring 158 within the opener body 140
(see also FIGS. 8 and 9).
Alternatively, a series of detents (not shown), each with a distally facing
camming surface and a proximally facing radial surface could be provided
within the opener body 140, axially adjacent the posts 152. The
mist-filter screen 160 would thus have a diameter equal to the inside
diameter of the opener body 140 and be held between the posts 152 and the
proximally facing surfaces of the detents. The screen could be easily
inserted through the opener distal end 144 and cammed over the detent
camming surfaces into place between the posts 152 and detents.
The safety ring 106 separates the opener 104 from the capsule 102. With the
safety ring 106 trapped between the opener body proximal end 142 and the
lip 115 on the capsule 102, the spike 146 is prevented from contacting the
membrane wall 116 (see also FIG. 8). The safety ring 106 is provided with
a thin wall section 164 and a diametrically opposed pull tab 166 whereby
manual pressure applied to the pull tab 166 is sufficient to deform the
thin wall section 164 beyond its elastic limit, preferably breaching the
thin wall section 164, thereby permitting removal of the safety ring 106
from the device 100.
FIG. 8 illustrates the assembled device 100 prior to use, with an adapter
170 affixed thereto. The adapter 170 comprises a cylindrical tubular body
172 formed of a soft thermoplastic elastomer, such as Schafer, GmbH
THEKA-FLEX, S 2030 M. A shallow inwardly facing annular flange 174 at a
proximal end 176 of the adapter body 172 is received within a
correspondingly shallow annular groove about the opener body 140 to hold
the adapter 170 to the device 100.
A truncated cone 178 extends inwardly, proximally, from a distal end 180 of
the adapter body 172 and terminates in a central opening 182. A luer
fitting 184 of an instrument to be sterilized 186 having a lumen 188
therein, is shown received within the opening 182. Those of skill in the
art will appreciate that the dimensions of the cone 178 can be varied to
accommodate various types of instruments to be sterilized and that other
engaging means may be substituted therefor.
To use the device 100, an appropriately sized adapter 170 is selected for
the particular instrument 186 to be sterilized. The adapter 170 is
attached to the device 100 as shown in FIG. 8. The pull-tab 166 on the
safety ring 106 is grasped and pulled to separate the safety ring thin
wall section 164 and remove the safety ring 106 from the device 100. To
aid the user in removing the safety ring 106 and in later rotating the
capsule 102 relative to the opener 104, the opener body 140 is provided
with several textured finger indentations 190 for easier grasping. After
the safety ring 106 is removed, the capsule 102 and opener 104 are pushed
together so that the spike 146 breaches the membrane wall 116 as shown in
FIG. 9. Preferably, the capsule 102 is then rotated one full turn to
ensure proper breaching of the membrane wall 116. The antimicrobial 122 is
then free to leave the chamber 124 and flow into the instrument lumen 188.
In general practice, the device 100, with adapter 172 and instrument 186
attached as the membrane wall breached 116 as shown in FIG. 9 are then
placed into the sterilization chamber (not shown ) of a solution vapor
sterilizer (also not shown). A vacuum applied to the sterilization chamber
causes the antimicrobial 122 to vaporize and migrate into the instrument
lumen 188 to effect sterilization thereof.
FIGS. 10 to 13 illustrate a further embodiment of a device 200 according to
the invention. The device 200 is similar in nearly all respects to the
device 100 with the exception of the following differences. Accordingly,
portions of the device 200 which are identical to the device 100 and were
previously described with respect thereto, will be designated with like
referenced numerals having a prime symbol (').
To reduce the force a user must exert to breach the membrane wall 116', the
capsule 102' threads into the opener 104'. A raised embossment 202
surrounds the capsule body 108' adjacent the lip 115'. A pair of threads
204 formed in the embossment 202 receive, respectfully, a pair of pins 206
which project into the opener body 140'. Each thread 204 comprises a
camming portion 208 and a circumferential portion 210.
The pins 206 enter the threads 204 through the camming portions 208 as the
capsule 102' is rotated relative to the opener 104', thereby pulling the
capsule 102' axially into the opener 104'. The circumferential portion 210
of the threads 204 allows the capsule 102' to be rotated an additional one
quarter turn after it is fully received within the opener 104' to insure
proper breaching of the membrane wall 116'.
In the previous embodiment, the interaction of the central flange 134 and
the opener body 140 seals the capsule 102 to the opener 104 to prevent
antimicrobial 122 from leaking out of the device 100 between the capsule
102 and opener 104. In the present embodiment, an O-ring 212 about the
capsule body 108' replaces the central flange 136 and engages the opener
body 140' to seal the capsule 102' therein.
In the previous embodiment, the spike 146 is provided with a simple
bevelled tip 148 to penetrate the membrane wall 116. In the present
embodiment, the bevelled tip 148 is replaced by a cutting tip 214 which is
placed off of the central axles of the spike 146' and which acts in a
fashion similar to that of a can opener to cut open the membrane wall 116.
It will be understood that the cutting tip 214 may take various forms,
however a sharp apex 216 and a sharp leading cutting edge 218 improve its
cutting ability.
Proper breaching of the membrane wall 116' is a prerequisite to adequate
sterilization. Accordingly, operators of the devices 100 or 200 prefer
some tactile, audible, visual or other feedback that the device has been
operated properly. In the previous embodiment, breaching of the membrane
wall 116 tends to occur suddenly, thus driving the capsule 102 and opener
104 together in a violent manner creating both an audible and tactile
snap. Also, the lip 115 will abut or closely approach the capsule body
proximal end 142 in this position to provide a visual indication of proper
operation.
In the present embodiment, the threading interaction between the capsule
102' and opener 104' breaches the membrane wall 116' more gently than in
the previous embodiment. Thus, the user receives less tactile feedback
that the membrane wall 116' has been breached. It may be desirable to
provide such feedback in the form of a snapping interaction between parts
on the capsule 102' and opener 104' or perhaps to provide a visual
indication or other feedback that the opener 104' is fully actuated.
FIGS. 12 and 13 illustrate one method of providing such feedback. As each
pins 206 travels its respective thread circumferential portion 210, it
encounters a detent 220. The pins 206 cam over the detents 220 and snap
over a sharp trailing edge 222 thereon to become trapped beyond the
detents 220. Thus, the detents 220 provide both an audible and tactile
feedback that the proper interaction has been achieved between the capsule
102' and opener 104'. Further, they prevent the capsule 102' and opener
104', and further prevent the capsule 102' from being easily backed out of
the opener 104'. Alignment marks (not shown) or other visual indicia mark
also be provided on the capsule 102' and opener 104' to indicate full
actuation.
Although the present invention has been described in terms of specific
devices for use in a preferred method of vapor sterilization, it will be
understood that various modifications in the device and method will be
apparent to those skilled in the art and are within the scope of this
invention.
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